One known form of cutting tool assembly of the kind to which the invention relates involves the so-called “wedge clamping” of the insert in the insert retaining slot. Here, the insert, having a single cutting edge, is provided with a wedge-shaped body which forcibly inserted and is retained within a correspondingly wedge-shaped retaining slot, the actual clamping of the insert within the slot being effected by the resilient outward displacement of the clamping jaw as a result of the forced insertion of the insert into the slot. With this type of cutting tool assembly, the resilient displacement of the jaw is effected by the insertion of the insert into the slot, but when it is desired to remove the insert, special means have to be provided for mechanically ejecting the insert from the slot, these means involving the direct exertion of an ejection pressure on the insert. It will be understood that both the insertion and removal of the insert is accompanied by significant friction with consequent wear on the blade jaws which are, in general, of a much softer material than that of the insert.
Alternatively, it is known (GB 1379637) to introduce into and clamp an insert within an insert retaining slot by first of all mechanically displacing outwardly a resiliently clamping jaw, introducing the insert into the slot and then allowing the jaw to spring back on to the insert in a clamping position. When it is desired to remove the insert from the slot, the clamping jaw is again displaced outwardly, allowing for the removal of the insert. The outward displacement of the jaw is effected using a mechanical key which is displaced in frictional contact with the inside of the clamping jaw, thereby leading to frictional wear of the jaw and/or the key.